Of all the sexually transmitted diseases, Trichomoniasis is the most common non-viral infection. An estimated 200 million people are infected annually all over the world, with greater than four million new cases per year in the United States alone. The agent of the disease, Trichomonas vaginalis, is a protozoan parasite with four anterior flagella and a recurrent flagellum. Trichomoniasis has recently been associated with severe complications such as development of cervical cancer, high probability of infection by human immunodeficiency virus and adverse pregnancy outcomes. In spite of the high incidence of trichomoniasis and the complications associated with the disease, the mechanisms of pathogenesis of the parasite are not well understood and some drug resistant strains of T. vaginalis are emerging. Therefore, there is urgent need for research in the area of subcellular structures of the parasite for; (a) adhesion molecules whose antisera will be of prophylactic value (b) discovery of new targets for anti-parasitic drugs (c) better understanding (immunobiology and functions) of the subcellular structures of the parasite. Our Preliminary Studies revealed several flagellar polypeptides that showed strong immuno-reactivity with human anti-Trichomoniasis sera in immunoblots. Furthermore, studies from different laboratories have shown that T. vaginalis cells are immunogenic in humans and laboratory animals. Based on these reports and our Preliminary Studies we hypothesize that flagellar proteins of the parasite are involved in adhesion of the parasite to the host cells. This hypothesis will be tested by isolating flagella followed by immunoprecipitation and analysis of flagellar antigens on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SOSPAGE). The flagellar antigens will be used to immunize rabbits and the rabbit antisera will be utilized to screen the parasite for adhesion inhibition. Flagellar antigens whose antisera show significant degree of adhesion inhibition will be considered to be flagellar adhesins. The role of the adhesins as ligands in the cytoadhesion of the parasite to host cells will be tufty examined by adhesion/adhesion inhibition assays. The adhesins will be characterized to know if they are surface exposed and the biochemical make up of the reacting epitopes. It is anticipated that the results of these studies will yield new information about the roles of flagellar proteins in the pathogenesis of T. vaginatis. [unreadable] [unreadable]